package com.example.project.filter;

/**
 *权限拦截器。
 */

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.example.project.annotations.PassToken;
import com.example.project.annotations.UserLoginToken;
import com.example.project.entity.User;
import com.example.project.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.Date;

@Slf4j
public class AuthenticationInterceptor implements HandlerInterceptor {
    @Autowired
    private UserService userService;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest,
                             HttpServletResponse httpServletResponse, Object object) throws Exception {
        //通过所有OPTION请求
        if(httpServletRequest.getMethod().toUpperCase().equals("OPTIONS")){
            return true;
        }

        String token = httpServletRequest.getHeader("Authorization");// 从 http 请求头中取出 token
        String refreshToken = httpServletRequest.getHeader("freshToken");// 从 http 请求头中取出 token

        log.info("token:" + token);
        log.info("refreshToken: " + refreshToken);

        // 如果该请求不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();

        //检查是否有passtoken注释，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                log.info("跳过验证!!!");
                return true;
            }
        }

        // 获取 token 中的 用户信息
        String userValue = null;

        try {
            userValue = JWT.decode(token).getAudience().get(0);

        } catch (JWTDecodeException j) {
            throw new RuntimeException("401");
        }
        log.info("userId: " + Long.parseLong(userValue));
//        Map<String, Object> map = new HashMap<>();
//        map.put("level", (userValue).substring(0,1));
        // 查看user是否存在
        User user = userService.findUser(Long.parseLong(userValue));

        if (user == null) {
            throw new RuntimeException("用户不存在，请重新登录");
        }

        Date oldTime = JWT.decode(token).getExpiresAt();
        Date refreshTime = JWT.decode(refreshToken).getExpiresAt();
        long oldDiff = oldTime.getTime() - new Date().getTime(); //这样得到的差值是毫秒级别
        long refreshDiff = refreshTime.getTime() - new Date().getTime(); //这样得到的差值是毫秒级别
        log.info(String.valueOf(oldDiff));
        log.info(String.valueOf(refreshTime));
        if (oldDiff <= 0) {
            if (refreshDiff <= 0) {
                httpServletResponse.sendError(401);
                throw new RuntimeException("401");
            }
        }
        String newToken = userService.getToken(user, 60* 60 * 1000);
        String newRefToken = userService.getToken(user, 24*60*60*1000);

        // 更新token
        httpServletResponse.setHeader("Authorization", newToken);
        httpServletResponse.setHeader("freshToken", newRefToken);

        //检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(UserLoginToken.class)) {  // 是否使用@UserLoginToken注解
            UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
            if (userLoginToken.required()) {
                // 执行认证
                if (token == null) {
                    throw new RuntimeException("=== 无token，请重新登录 ===");
                }
                // 利用用户密码，解密验证 token
                JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
                try {
                    jwtVerifier.verify(token);
                } catch (JWTVerificationException e) {
                    System.out.println("=== token验证失败 ===");
                    httpServletResponse.sendError(401);
                    throw new RuntimeException("401");
                }
                return true;
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }
}
